How do I change windows proxies with username pass?

Hello I like to know how do I change global proxy not registry method but IP: Port: Username: Password inside my vb.net app. When I use "credentials" the remote server return error. Credentials are correct. My residential proxy provider gave me formate so I have to use user and pass too, instead of IP auth. If I used before IP auth I simply added IP: Port in windwows settings and thats it, but there is no place for username and pass , I also used some "proxyfier" but trial is gone and I want to build onw small proxy changer. Thank you guys.

IEProxy class:

Imports System
Imports System.Runtime.InteropServices

Public Class IEProxy
    Public Enum Options
        INTERNET_PER_CONN_FLAGS = 1
        INTERNET_PER_CONN_PROXY_SERVER = 2
        INTERNET_PER_CONN_PROXY_BYPASS = 3
        INTERNET_PER_CONN_AUTOCONFIG_URL = 4
        INTERNET_PER_CONN_AUTODISCOVERY_FLAGS = 5
        INTERNET_OPTION_REFRESH = 37
        INTERNET_OPTION_PER_CONNECTION_OPTION = 75
        INTERNET_OPTION_SETTINGS_CHANGED = 39
        PROXY_TYPE_PROXY = &H2
        PROXY_TYPE_DIRECT = &H1
    End Enum

    <StructLayout(LayoutKind.Sequential)>
    Private Class FILETIME
        Public dwLowDateTime As Integer
        Public dwHighDateTime As Integer
    End Class

    <StructLayout(LayoutKind.Explicit, Size:=12)>
    Private Structure INTERNET_PER_CONN_OPTION
        <FieldOffset(0)> Dim dwOption As Integer
        <FieldOffset(4)> Dim dwValue As Integer
        <FieldOffset(4)> Dim pszValue As IntPtr
        <FieldOffset(4)> Dim ftValue As IntPtr

        Public Function GetBytes() As Byte()
            Dim b(12) As Byte
            BitConverter.GetBytes(dwOption).CopyTo(b, 0)
            Select Case dwOption
                Case Options.INTERNET_PER_CONN_FLAGS
                    BitConverter.GetBytes(dwValue).CopyTo(b, 4)
                Case Options.INTERNET_PER_CONN_PROXY_BYPASS
                    BitConverter.GetBytes(pszValue.ToInt32()).CopyTo(b, 4)
                Case Options.INTERNET_PER_CONN_PROXY_SERVER
                    BitConverter.GetBytes(pszValue.ToInt32()).CopyTo(b, 4)
            End Select
            Return b
        End Function
    End Structure

    <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Auto)>
    Private Class INTERNET_PER_CONN_OPTION_LIST
        Public dwSize As Integer
        Public pszConnection As String
        Public dwOptionCount As Integer
        Public dwOptionError As Integer
        Public pOptions As IntPtr
    End Class

    <StructLayout(LayoutKind.Sequential)>
    Private Class INTERNET_PROXY_INFO
        Public dwAccessType As Integer
        Public lpszProxy As IntPtr
        Public lpszProxyBypass As IntPtr
    End Class

    Private Const ERROR_INSUFFICIENT_BUFFER = 122
    Private Const INTERNET_OPTION_PROXY = 38
    Private Const INTERNET_OPEN_TYPE_DIRECT = 1

    <DllImport("wininet.dll")>
    Private Shared Function InternetSetOption(ByVal hInternet As IntPtr,
             ByVal dwOption As Integer,
             ByVal lpBuffer As INTERNET_PER_CONN_OPTION_LIST,
             ByVal dwBufferLength As Integer) As Boolean
    End Function

    <DllImport("kernel32.dll")>
    Private Shared Function GetLastError() As Integer
    End Function

    Public Function SetProxy(ByVal proxy_full_addr As String) As Boolean
        Dim bReturn As Boolean
        Dim list As New INTERNET_PER_CONN_OPTION_LIST
        Dim dwBufSize As Integer = Marshal.SizeOf(list)
        Dim opts(3) As INTERNET_PER_CONN_OPTION
        Dim opt_size As Integer = Marshal.SizeOf(opts(0))

        list.dwSize = dwBufSize
        list.pszConnection = ControlChars.NullChar
        list.dwOptionCount = 3

        'set flags
        opts(0).dwOption = Options.INTERNET_PER_CONN_FLAGS
        opts(0).dwValue = Options.PROXY_TYPE_DIRECT Or Options.PROXY_TYPE_PROXY

        'set proxyname
        opts(1).dwOption = Options.INTERNET_PER_CONN_PROXY_SERVER
        opts(1).pszValue = Marshal.StringToHGlobalAnsi(proxy_full_addr)

        'set override
        opts(2).dwOption = Options.INTERNET_PER_CONN_PROXY_BYPASS
        opts(2).pszValue = Marshal.StringToHGlobalAnsi("local")

        Dim b(3 * opt_size) As Byte
        opts(0).GetBytes().CopyTo(b, 0)
        opts(1).GetBytes().CopyTo(b, opt_size)
        opts(2).GetBytes().CopyTo(b, 2 * opt_size)

        Dim ptr As IntPtr = Marshal.AllocCoTaskMem(3 * opt_size)
        Marshal.Copy(b, 0, ptr, 3 * opt_size)

        list.pOptions = ptr
        'Set the options on the connection
        bReturn = InternetSetOption(IntPtr.Zero, Options.INTERNET_OPTION_PER_CONNECTION_OPTION, list, dwBufSize)
        If Not bReturn Then
            Debug.WriteLine(GetLastError)
        End If

        'Notify existing Internet Explorer instances that the settings have changed
        bReturn = InternetSetOption(IntPtr.Zero, Options.INTERNET_OPTION_SETTINGS_CHANGED, Nothing, 0)
        If Not bReturn Then
            Debug.WriteLine(GetLastError)
        End If

        'Flush the current IE proxy setting
        bReturn = InternetSetOption(IntPtr.Zero, Options.INTERNET_OPTION_REFRESH, Nothing, 0)
        If Not bReturn Then
            Debug.WriteLine(GetLastError)
        End If

        Marshal.FreeHGlobal(opts(1).pszValue)
        Marshal.FreeHGlobal(opts(2).pszValue)
        Marshal.FreeCoTaskMem(ptr)
        Return bReturn
    End Function

    Public Function DisableProxy() As Boolean
        Dim bReturn As Boolean
        Dim list As New INTERNET_PER_CONN_OPTION_LIST
        Dim dwBufSize As Integer = Marshal.SizeOf(list)
        Dim opts(0) As INTERNET_PER_CONN_OPTION
        Dim opt_size As Integer = Marshal.SizeOf(opts(0))

        list.dwSize = dwBufSize
        list.pszConnection = ControlChars.NullChar
        list.dwOptionCount = 1

        opts(0).dwOption = Options.INTERNET_PER_CONN_FLAGS
        opts(0).dwValue = Options.PROXY_TYPE_DIRECT

        Dim b(opt_size) As Byte
        opts(0).GetBytes().CopyTo(b, 0)

        Dim ptr As IntPtr = Marshal.AllocCoTaskMem(opt_size)
        Marshal.Copy(b, 0, ptr, opt_size)

        list.pOptions = ptr
        'Set the options on the connection
        bReturn = InternetSetOption(IntPtr.Zero, Options.INTERNET_OPTION_PER_CONNECTION_OPTION, list, dwBufSize)
        If Not bReturn Then
            Debug.WriteLine(GetLastError)
        End If

        'Notify existing Internet Explorer instances that the settings have changed
        bReturn = InternetSetOption(IntPtr.Zero, Options.INTERNET_OPTION_SETTINGS_CHANGED, Nothing, 0)
        If Not bReturn Then
            Debug.WriteLine(GetLastError)
        End If

        'Flush the current IE proxy setting
        bReturn = InternetSetOption(IntPtr.Zero, Options.INTERNET_OPTION_REFRESH, Nothing, 0)
        If Not bReturn Then
            Debug.WriteLine(GetLastError)
        End If

        Marshal.FreeCoTaskMem(ptr)
        Return bReturn
    End Function
End Class

Then I call this from button:

Private Sub btnconnect_Click(sender As Object, e As EventArgs) Handles btnConnectDisconnect.Click

        Dim clsProxy As New IEProxy
        If My.Settings.IEProxyConnected Then
            If clsProxy.DisableProxy Then
                btnConnectDisconnect.Text = "Connect"
                My.Settings.IEProxyConnected = False
                RunCMD()
                MessageBox.Show("Proxy successfully disabled.", "Success", MessageBoxButtons.OK, MessageBoxIcon.Information)
            Else
                MessageBox.Show("Error disabling proxy.", "Failed", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
            End If
        Else
            If Not (String.IsNullOrEmpty(txtIP.Text) Or String.IsNullOrEmpty(txtPort.Text)) Then
                Dim port As Integer
                'Dim proxyIP_user As String = txtUser.Text
                'Dim proxyIP_pass As String = txtPass.Text

                If Integer.TryParse(txtPort.Text, port) Then
                    Dim p As WebProxy = New WebProxy(txtIP.Text.Trim, port)
                    'Dim credentials As ICredentials = New NetworkCredential(proxyIP_user, proxyIP_pass)
                    '  Dim p As WebProxy = New WebProxy(txtIP.Text, True, Nothing, )



                    My.Settings.RootProxy = p
                    'My.Settings.credentials = credentials
                    My.Settings.Save()

                    If clsProxy.SetProxy(p.Address.Host & ":" & p.Address.Port) Then
                        btnConnectDisconnect.Text = "Disconnect"
                        My.Settings.IEProxyConnected = True
                        MessageBox.Show("Proxy successfully enabled.", "Success", MessageBoxButtons.OK, MessageBoxIcon.Information)
                    Else
                        MessageBox.Show("Error enabling proxy.", "Failed", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
                    End If
                End If
            Else

            End If
        End If
        My.Settings.Save()
    End Sub